It would be interesting to have been a fly on the wall during the board meeting in which the £135,000 Jaguar XKR-S GT was given the green light - because this, after all, is not a car that’s likely to bolster Jaguar Land Rover’s profit margins, despite its knee-trembling price tag.

Even so, it’s an important car for the company because, if nothing else, it shows just how boldly Jaguar is thinking nowadays. A decade ago a car as wild as the bespoilered, bewinged, 186mph XKR-S GT wouldn’t have been given a moment’s thought by the Jaguar brass, but now it’s here, in the flesh, grabbing the headlines and running with them in a manner that is totally out of proportion to the amount of money it cost to develop.

How they get this past the noise police I have no idea, but it sounds cartoonishly loud.

Jaguar announced to the world that it would build just 30 such examples, each of which would be left-hand drive and destined for the US market. Which is when the XKR-S GT story got even more interesting.

Because as soon as that initial run of LHD cars was announced, the phones at JLR began to ring. And ring. There were quite a few more people interested in buying an XKR-S GT than Jaguar’s board imagined. Hence the reason why the car you see here appears in right, not left, hand drive: Jaguar now says it’ll make at least 10 more cars for the RHD market, possibly as much as 20 if there is the demand.

So I guess the question is this; is the XKR-S GT worth all the hoopla that surrounds it? Does it drive as good as it looks? Or is it ultimately just a great big marketing exercise; a vehicle that carries a message - and a very big rear spoiler - but not much else when push comes to shove?

In engineering terms, it would certainly appear to be the real deal. Although the 5.0-litre supercharged V8 engine and six-speed automatic is unchanged from the regular XKR-S (the engine produces identical outputs of 542bhp and 502lb ft), there is much that is new beneath the GT’s more flamboyant exterior. Gone are the rear seats, replaced by a full roll cage. The front seats are lighter and far more supportive racing buckets, both with a full four-point harness seatbelt. But it’s the chassis and suspension – and the brakes – that have received the greatest attention.

In essence, the GT would appear to be a kind of rolling test bed for most of the good stuff that will eventually make its way into the hottest versions of the F-type coupé. The rear axle is new, much of the front suspension hardware has been replaced (and will appear in the F-type), the front track is a whopping 52mm wider (although the rear track remains unchanged) while the uprights, springs and dampers will each, in various forms, make their way into future quick Jaguars.

The brake discs are carbon ceramic, with huge 398mm rotors at the front and 380mm at the rear, thereby addressing one of the key criticisms of the regular XKR-S – that it can’t quite stop as well as it can go. Which is always a touch concerning when there’s one and three quarter tonnes of car to keep in check, although in this case the kerb weight has dropped by 40kg to a still hefty 1713kg.

Bottom line; the XKR-S GT doesn’t just stop better than the car on which it’s based, it’s also nearly 70 per cent stiffer at the front and 25 per cent stiffer at the back. Couple this with the wider front track, a set of fatter, stickier Pirelli P-Zero Corsa tyres (255 section front, 305 rear) and some 145kg of downforce courtesy of that big rear wing and some additional new winglets at the front, and what you end up with – in theory – is a very different animal indeed from the already quite wild XKR-S.

A car that can lap the Nürburgring, indeed, in some 7min 40sec, which is about where the original version of the current Nissan GT-R was when it tore the rest of the world – including the Nordschleife – to shreds not that many years ago.

If nothing else, the XKR-S GT’s 0-60mph time goes a reasonable way towards justifying its price on its own, at an impressively scant 3.9sec. What we are talking about here is a car with a surfeit of performance, in other words. A machine whose potential you might not ever exploit fully on the public road.

And yet, as it turns out, the GT is actually a rather pleasant car to drive on a public road, with a surprisingly compliant ride, lovely steering feel, not too much noise from its vast rear tyres despite the removal of those rear seats, and a far more civilised personality in general than you’d expect, given the way it looks.

On the road it feels stiffer and more controlled than the regular RS; there would be something strange going on were this not the case. But despite the extra control and the new-found absence of roll or lurch when changing direction quickly, it doesn’t feel compromised in terms of its ride quality.

It’s firmer than normal, yes, but it still feels like a Jaguar on the move over a typical UK B-road. The compromise it strikes here is more successful than that of the recent XFR-S, it must be noted, which, to be blunt, is almost too stiff for everyday road use.

Secondary observations on the road; it really does steer beautifully; on a dry surface the Corsas stick like the proverbial you-know-what to a blanket; the gearbox can never quite make its mind up which ratio it wants to be in, even if you select “sport” mode which, in theory, should mean it holds on to whatever gear you select manually.

The noise that erupts out of the four tailpipes if you give it full beans beyond 3000rpm is 110 per cent outrageous – to a point where pedestrians dive for cover, literally, if you are heartless enough to keep your toe in as you howl past.

Conclusion; on the road (preferably a dry one, although even on wet surfaces it proved to be a lot less of a handful than we expected) the Jaguar XKR-S GT is, well, something of a revelation truth be told.

You look at its wings and skirts and its ultra low ride height, then read the specification sheet and discover that it’s two times stiffer than normal, and think; this is going to be an unbearably uncomfortable, totally uncompromising, mostly unnecessary way to spend £135,000 on a Jaguar and give yourself a huge dentistry bill in the process.

But what you discover is, despite appearances, a really rather lovely car to drive. Not a Porsche 911 GT3 rival but, instead, something almost as quick and a fair bit more usable into the bargain.

What’s it like on a track? As we discovered at Castle Combe, not bad, not bad at all. And, so long as it’s not too damp, also very quick indeed against the clock.

Jaguar's decision to build more XKR-S GTs proves the model deserves its place in the world, and then some. It’s way more than just a statement of intent.